1. Field of the Invention
The present invention relates to a skateboard having a three-dimensional independent suspension balance system, and more particularly to a skateboard, wherein each of the rollers has independent horizontal and vertical displacement, thereby forming an excellent balance effect, so that the skateboard can be moved in a stable manner.
2. Description of the Related Art
A first conventional skateboard 10B in accordance with the prior art shown in FIGS. 15-17 comprises a board body 11B, two bases 12B each mounted on the bottom of the board body 11B, and two wheel seats 13B each mounted on the bottom of a respective one of the two bases 12B for supporting two rollers 14B by a wheel axle 15B.
However, the first conventional skateboard 10B has the following disadvantages.
1. Each of the two wheel seats 13B can be rotated through a little angle only, thereby causing instability when the skateboard 10B is turned, and thereby affecting the user's safety.
2. As shown in FIG. 15, each of the two wheel seats 13B can be rotated through a little angle only, so that the rotation diameter “R” of the board body 11B is very large, thereby decreasing mobility of the skateboard 10B when turning.
3. As shown in FIG. 16, when either one roller 14B is blocked, the roller 14B produces a height differential ΔH, and the board body 11B produces a larger height differential ΔH′, thereby decreasing stability of the skateboard 10B when moving.
4. When the rollers 14B are subjected to shock or vibration, the shock or vibration is directly transmitted to the board body 11B, thereby causing an uncomfortable sensation to the user.
5. As shown in FIG. 17, when either roller 14B is blocked, one of the two wheel seats 13B is deflected and directed toward the direction “D1” which deviates from the travel direction “D0” of the skateboard 10B, thereby decreasing stability of the skateboard 10B when moving.
A second conventional skateboard 10C in accordance with the prior art shown in FIGS. 18 and 19 comprises a board body 11C, and two bases 12C each mounted on the bottom of the board body 11C. Each of the two bases 12C is provided with a rotation disk 16C having two ends each pivoted with a primary wheel arm 17C which is provided with a roller 14C. The primary wheel arm 17C has a mediate portion provided with a secondary wheel arm 18C which is pivotally connected with a drawing arm 19C which is extended through the base 12C.
However, the second conventional skateboard 10C has the following disadvantages.
1. The second conventional skateboard 10C is expensive, thereby increasing costs of fabrication.
2. The second conventional skateboard 10C has a heavy weight and a large volume, thereby causing inconvenience to the user in transportation and storage.
3. The primary wheel arm 17C is interconnected with the secondary wheel arm 18C, thereby affecting displacement of the roller 14C at the other end, and thereby decreasing stability of the skateboard 10C when moving.
4. The second conventional skateboard 10C has a higher center of gravity, thereby decreasing stability of the skateboard 10C when moving.
5. Each of the rollers 14C is distantly spaced from the board body 11C, so that the user's one foot easily hits the roller 14C, thereby causing inconvenience in use.
The closest prior art references of which the applicant is aware are disclosed in U.S. Pat. No. 5,263,725 and U.S. Pat. No. 5,997,018.